I recently got a rMBP 13" late 2013 and this machine feels very well put together and premium but It'll be in a sleeve and in a backpack everyday.. Anybody ever have any durability issues with their MBP? Drop a comment, it's appreciated 
I bought a Speck SeeThru for my rMBP because not only do I have my laptop in transport all the time (laptop bag), but I'll be going to camp this summer to work, some extra protection is always good. I recommend this case if it's something you're looking at. They can be found for less than MSRP price on Amazon, just make sure you read the reviews.
The additional weight is very minimal, and the added thickness of the machine isn't too bad, It's still thinner than a none retina MBP. I think it may depend on what case color. I have the crystal finish clear so it's pretty much invisible except around the edges.Speck SeeThru looks really nice. But...
-I wonder about the addition in weight.
-Is it slim or does it look bulky?
-What about heat dissipation?
Dust:
My main concern is not scratches, but dust.
Till now I use a handmade(by me) cover for use when I am not working on it. Just to keep the dust away.
I do not think that this can help with the dust.
What do you think about it?